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<head><meta charset="utf-8"><title>MPL in cg_clif · t-core/licensing · Zulip Chat Archive</title></head>
<h2>Stream: <a href="https://rust-lang.github.io/zulip_archive/stream/231349-t-core/licensing/index.html">t-core/licensing</a></h2>
<h3>Topic: <a href="https://rust-lang.github.io/zulip_archive/stream/231349-t-core/licensing/topic/MPL.20in.20cg_clif.html">MPL in cg_clif</a></h3>

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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/231349-t-core/licensing/topic/MPL%20in%20cg_clif/near/238024032" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> bjorn3 <a href="https://rust-lang.github.io/zulip_archive/stream/231349-t-core/licensing/topic/MPL.20in.20cg_clif.html#238024032">(May 09 2021 at 09:53)</a>:</h4>
<p>Cranelift may move to a new register allocator in the future[1]. This register allocator is a port of Spidermonkeys register allocator, which is licensed as MPL-2.0. For this reason it has to be MPL-2.0 licensed too. As I understand it, MPL is reciprocal, but not infectious due to only applying to individual files instead of the whole linked program like GPL. Is this an acceptable license for a dependency of cg_clif now that it will be distributed on nightly as rustup component in the near future?</p>
<p>[1]: <a href="https://github.com/bytecodealliance/regalloc2/pull/1">https://github.com/bytecodealliance/regalloc2/pull/1</a></p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/231349-t-core/licensing/topic/MPL%20in%20cg_clif/near/238024108" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> bjorn3 <a href="https://rust-lang.github.io/zulip_archive/stream/231349-t-core/licensing/topic/MPL.20in.20cg_clif.html#238024108">(May 09 2021 at 09:54)</a>:</h4>
<p>cc <span class="user-mention" data-user-id="327027">@Chris Fallin</span></p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/231349-t-core/licensing/topic/MPL%20in%20cg_clif/near/238050454" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Josh Triplett <a href="https://rust-lang.github.io/zulip_archive/stream/231349-t-core/licensing/topic/MPL.20in.20cg_clif.html#238050454">(May 09 2021 at 17:54)</a>:</h4>
<p>That would be a large change to Rust's licensing policy, as far as I know.</p>
<p>(Also, please don't use "infectious" to describe strong copyleft.)</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/231349-t-core/licensing/topic/MPL%20in%20cg_clif/near/238050482" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Josh Triplett <a href="https://rust-lang.github.io/zulip_archive/stream/231349-t-core/licensing/topic/MPL.20in.20cg_clif.html#238050482">(May 09 2021 at 17:55)</a>:</h4>
<p>Given that it isn't a dependency of std, it wouldn't necessarily be a practical problem, but it would nonetheless be a substantial change.</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/231349-t-core/licensing/topic/MPL%20in%20cg_clif/near/238054433" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> bjorn3 <a href="https://rust-lang.github.io/zulip_archive/stream/231349-t-core/licensing/topic/MPL.20in.20cg_clif.html#238054433">(May 09 2021 at 19:04)</a>:</h4>
<blockquote>
<p>(Also, please don't use "infectious" to describe strong copyleft.)</p>
</blockquote>
<p>I didn't mean it in a negative sense, but I get that it can be interpreted as such. I personally have nothing against GPL. In fact I have used it as license for several of my own projects.</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/231349-t-core/licensing/topic/MPL%20in%20cg_clif/near/238058750" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Chris Fallin <a href="https://rust-lang.github.io/zulip_archive/stream/231349-t-core/licensing/topic/MPL.20in.20cg_clif.html#238058750">(May 09 2021 at 20:17)</a>:</h4>
<p>Hmm, this is surprising to me, given that MPL code in (part of) the regalloc crate wouldn't impose any license requirements on any other code that uses it, but I will bring it up with some others. It's unfortunate that this didn't come up earlier, for sure! Thanks for raising the issue.</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/231349-t-core/licensing/topic/MPL%20in%20cg_clif/near/238095231" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Josh Triplett <a href="https://rust-lang.github.io/zulip_archive/stream/231349-t-core/licensing/topic/MPL.20in.20cg_clif.html#238095231">(May 10 2021 at 07:00)</a>:</h4>
<p>It's not necessarily a dealbreaker, but it'd be a first, and it would need discussion and approval.</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/231349-t-core/licensing/topic/MPL%20in%20cg_clif/near/238095439" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Josh Triplett <a href="https://rust-lang.github.io/zulip_archive/stream/231349-t-core/licensing/topic/MPL.20in.20cg_clif.html#238095439">(May 10 2021 at 07:02)</a>:</h4>
<p>Any non-permissive license in std/core/etc would be a complete non-starter. In something that would only be part of rustc, it would cause fewer logistical issues.</p>



<hr><p>Last updated: Aug 07 2021 at 22:04 UTC</p>
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